suppressing log when trying to send on closing websocket

wsclient.js

@@ -239,10 +239,14 @@ function run(copts) {
         try {
           wstunneler.send(msg, {binary: true});
         } catch (err) {
+          // There is a chance that this occurred after the websocket was told to close
+          // and before it finished, in which case we don't need to log the error.
+          if (wstunneler.readyState !== wstunneler.CLOSING) {
             console.warn('[sendMessage] error sending websocket message', err);
           }
         }
       }
+    }
   };
 
   function connect() {